Let me tell you then. Bank tellers are employees that deal directly with costumers
My mom was a bank teller.  They are the bank employees who deal directly with customers!
i would like to know about bank tellers
A bank teller (often abbreviated to simply teller) is an employee of a bank who deals directly with customers.
я хотел бы узнать больше о банковских кассирах
Банковский кассир (часто сокращенно просто кассир) - это сотрудник банка, который имеет дело непосредственно с клиентами.